ISIS

ISIS is a routing protocol which is described in ISO10589, RFC 1195, RFC 5308. ISIS is an IGP. Compared with RIP, ISIS can provide scalable network support and faster convergence times like OSPF. ISIS is widely used in large networks such as ISP and carrier backbone networks.

Configuring isisd

There are no isisd specific options. Common options can be specified (common-invocation-options) to isisd. isisd needs to acquire interface information from zebra in order to function. Therefore zebra must be running before invoking isisd. Also, if zebra is restarted then isisd must be too.

Like other daemons, isisd configuration is done in ISIS specific configuration file isisd.conf.

ISIS router

To start the ISIS process you have to specify the ISIS router. As of this writing, isisd does not support multiple ISIS processes.

[no] router isis WORD: Enable or disable the ISIS process by specifying the ISIS domain with ‘WORD’. isisd does not yet support multiple ISIS processes but you must specify the name of ISIS process. The ISIS process name ‘WORD’ is then used for interface (see command ip router isis WORD).

net XX.XXXX. ... .XXX.XX

no net XX.XXXX. ... .XXX.XX: Set/Unset network entity title (NET) provided in ISO format.

hostname dynamic

no hostname dynamic: Enable support for dynamic hostname.

area-password [clear | md5] <password>

domain-password [clear | md5] <password>

no area-password

no domain-password: Configure the authentication password for an area, respectively a domain, as clear text or md5 one.

log-adjacency-changes

no log-adjacency-changes: Log changes in adjacency state.

metric-style [narrow | transition | wide]

no metric-style

Set old-style (ISO 10589) or new-style packet formats:

narrow Use old style of TLVs with narrow metric
transition Send and accept both styles of TLVs during transition
wide Use new style of TLVs to carry wider metric

set-overload-bit

no set-overload-bit: Set overload bit to avoid any transit traffic.

purge-originator

no purge-originator: Enable or disable RFC 6232 purge originator identification.

ISIS Timer

lsp-gen-interval (1-120)

lsp-gen-interval [level-1 | level-2] (1-120)

no lsp-gen-interval

no lsp-gen-interval [level-1 | level-2]: Set minimum interval in seconds between regenerating same LSP, globally, for an area (level-1) or a domain (level-2).

lsp-refresh-interval [level-1 | level-2] (1-65235)

no lsp-refresh-interval [level-1 | level-2]: Set LSP refresh interval in seconds, globally, for an area (level-1) or a domain (level-2).

max-lsp-lifetime (360-65535)

max-lsp-lifetime [level-1 | level-2] (360-65535)

no max-lsp-lifetime

no max-lsp-lifetime [level-1 | level-2]: Set LSP maximum LSP lifetime in seconds, globally, for an area (level-1) or a domain (level-2).

spf-interval (1-120)

spf-interval [level-1 | level-2] (1-120)

no spf-interval

no spf-interval [level-1 | level-2]: Set minimum interval between consecutive SPF calculations in seconds.

ISIS region

is-type [level-1 | level-1-2 | level-2-only]

no is-type

Define the ISIS router behavior:

level-1 Act as a station router only
level-1-2 Act as both a station router and an area router
level-2-only Act as an area router only

ISIS interface

[no] <ip|ipv6> router isis WORD: Activate ISIS adjacency on this interface. Note that the name of ISIS instance must be the same as the one used to configure the ISIS process (see command router isis WORD). To enable IPv4, issue ip router isis WORD; to enable IPv6, issue ipv6 router isis WORD.

isis circuit-type [level-1 | level-1-2 | level-2]

no isis circuit-type

Configure circuit type for interface:

level-1 Level-1 only adjacencies are formed
level-1-2 Level-1-2 adjacencies are formed
level-2-only Level-2 only adjacencies are formed

isis csnp-interval (1-600)

isis csnp-interval (1-600) [level-1 | level-2]

no isis csnp-interval

no isis csnp-interval [level-1 | level-2]: Set CSNP interval in seconds globally, for an area (level-1) or a domain (level-2).

isis hello padding: Add padding to IS-IS hello packets.

isis hello-interval (1-600)

isis hello-interval (1-600) [level-1 | level-2]

no isis hello-interval

no isis hello-interval [level-1 | level-2]: Set Hello interval in seconds globally, for an area (level-1) or a domain (level-2).

isis hello-multiplier (2-100)

isis hello-multiplier (2-100) [level-1 | level-2]

no isis hello-multiplier

no isis hello-multiplier [level-1 | level-2]: Set multiplier for Hello holding time globally, for an area (level-1) or a domain (level-2).

isis metric [(0-255) | (0-16777215)]

isis metric [(0-255) | (0-16777215)] [level-1 | level-2]

no isis metric

no isis metric [level-1 | level-2]: Set default metric value globally, for an area (level-1) or a domain (level-2). Max value depend if metric support narrow or wide value (see command metric-style [narrow | transition | wide]).

isis network point-to-point

no isis network point-to-point: Set network type to ‘Point-to-Point’ (broadcast by default).

isis passive

no isis passive: Configure the passive mode for this interface.

isis password [clear | md5] <password>

no isis password: Configure the authentication password (clear or encoded text) for the interface.

isis priority (0-127)

isis priority (0-127) [level-1 | level-2]

no isis priority

no isis priority [level-1 | level-2]: Set priority for Designated Router election, globally, for the area (level-1) or the domain (level-2).

isis psnp-interval (1-120)

isis psnp-interval (1-120) [level-1 | level-2]

no isis psnp-interval

no isis psnp-interval [level-1 | level-2]: Set PSNP interval in seconds globally, for an area (level-1) or a domain (level-2).

isis three-way-handshake

no isis three-way-handshake: Enable or disable RFC 5303 Three-Way Handshake for P2P adjacencies. Three-Way Handshake is enabled by default.

Showing ISIS information

show isis summary: Show summary information about ISIS.

show isis hostname: Show information about ISIS node.

show isis interface

show isis interface detail

show isis interface <interface name>: Show state and configuration of ISIS specified interface, or all interfaces if no interface is given with or without details.

show isis neighbor

show isis neighbor <System Id>

show isis neighbor detail: Show state and information of ISIS specified neighbor, or all neighbors if no system id is given with or without details.

show isis database

show isis database [detail]

show isis database <LSP id> [detail]

show isis database detail <LSP id>: Show the ISIS database globally, for a specific LSP id without or with details.

show isis topology

show isis topology [level-1|level-2]: Show topology IS-IS paths to Intermediate Systems, globally, in area (level-1) or domain (level-2).

show ip route isis: Show the ISIS routing table, as determined by the most recent SPF calculation.

Debugging ISIS

debug isis adj-packets

no debug isis adj-packets: IS-IS Adjacency related packets.

debug isis checksum-errors

no debug isis checksum-errors: IS-IS LSP checksum errors.

debug isis events

no debug isis events: IS-IS Events.

debug isis local-updates

no debug isis local-updates: IS-IS local update packets.

debug isis packet-dump

no debug isis packet-dump: IS-IS packet dump.

debug isis protocol-errors

no debug isis protocol-errors: IS-IS LSP protocol errors.

debug isis route-events

no debug isis route-events: IS-IS Route related events.

debug isis snp-packets

no debug isis snp-packets: IS-IS CSNP/PSNP packets.

debug isis spf-events

debug isis spf-statistics

debug isis spf-triggers

no debug isis spf-events

no debug isis spf-statistics

no debug isis spf-triggers: IS-IS Shortest Path First Events, Timing and Statistic Data and triggering events.

debug isis update-packets

no debug isis update-packets: Update related packets.

show debugging isis: Print which ISIS debug level is activate.

ISIS Configuration Examples

A simple example, with MD5 authentication enabled:

!
interface eth0
 ip router isis FOO
 isis network point-to-point
 isis circuit-type level-2-only
!
router isis FOO
net 47.0023.0000.0000.0000.0000.0000.0000.1900.0004.00
 metric-style wide
 is-type level-2-only